Holographic Schwinger Effect In a Step Dilaton Background

TL;DR

This paper explores how a step dilaton background in holography enhances the Schwinger effect, showing increased sensitivity to external fields and a sharper potential barrier suppression compared to smooth models.

Contribution

It introduces a confining holographic model with a step dilaton profile that significantly amplifies the Schwinger effect and its response to magnetic fields, revealing new non-perturbative dynamics.

Findings

Sharper suppression of potential barrier with increasing electric field.

Enhanced critical electric field sensitivity due to the step dilaton.

Pronounced shift in the potential barrier caused by external magnetic fields.

Abstract

We investigate the holographic Schwinger effect in a confining background with a step dilaton profile, which induces a sharp transition between ultraviolet and infrared regimes and provides a qualitatively distinct realization of confinement. Within this framework, the quark--antiquark potential is extracted from the classical configuration of a fundamental string, allowing for a direct analysis of vacuum instability and pair production. In the absence of a magnetic field, the step dilaton leads to a significantly sharper suppression of the potential barrier as the electric field increases, implying an enhanced sensitivity of the critical electric field compared to smooth soft-wall models and demonstrating that the abrupt geometric transition qualitatively enhances the onset of vacuum decay. Incorporating an external magnetic field through the Dirac--Born--Infeld action, we find a nontrivial and amplified deformation of the potential barrier, resulting in a pronounced shift of the critical electric field that depends on both the magnitude and orientation of the magnetic field. Overall, the step dilaton background exhibits a substantially stronger response of the Schwinger effect to external electromagnetic fields than conventional soft-wall models, providing a novel mechanism for controlling pair production and highlighting the crucial role of dilaton structure in non-perturbative dynamics of holographic QCD.